| /* |
| * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_MEMORY_DEFNEWGENERATION_HPP |
| #define SHARE_VM_MEMORY_DEFNEWGENERATION_HPP |
| |
| #include "gc_implementation/shared/ageTable.hpp" |
| #include "gc_implementation/shared/cSpaceCounters.hpp" |
| #include "gc_implementation/shared/generationCounters.hpp" |
| #include "gc_implementation/shared/copyFailedInfo.hpp" |
| #include "memory/generation.inline.hpp" |
| #include "utilities/stack.hpp" |
| |
| class EdenSpace; |
| class ContiguousSpace; |
| class ScanClosure; |
| class STWGCTimer; |
| |
| // DefNewGeneration is a young generation containing eden, from- and |
| // to-space. |
| |
| class DefNewGeneration: public Generation { |
| friend class VMStructs; |
| |
| protected: |
| Generation* _next_gen; |
| uint _tenuring_threshold; // Tenuring threshold for next collection. |
| ageTable _age_table; |
| // Size of object to pretenure in words; command line provides bytes |
| size_t _pretenure_size_threshold_words; |
| |
| ageTable* age_table() { return &_age_table; } |
| |
| // Initialize state to optimistically assume no promotion failure will |
| // happen. |
| void init_assuming_no_promotion_failure(); |
| // True iff a promotion has failed in the current collection. |
| bool _promotion_failed; |
| bool promotion_failed() { return _promotion_failed; } |
| PromotionFailedInfo _promotion_failed_info; |
| |
| // Handling promotion failure. A young generation collection |
| // can fail if a live object cannot be copied out of its |
| // location in eden or from-space during the collection. If |
| // a collection fails, the young generation is left in a |
| // consistent state such that it can be collected by a |
| // full collection. |
| // Before the collection |
| // Objects are in eden or from-space |
| // All roots into the young generation point into eden or from-space. |
| // |
| // After a failed collection |
| // Objects may be in eden, from-space, or to-space |
| // An object A in eden or from-space may have a copy B |
| // in to-space. If B exists, all roots that once pointed |
| // to A must now point to B. |
| // All objects in the young generation are unmarked. |
| // Eden, from-space, and to-space will all be collected by |
| // the full collection. |
| void handle_promotion_failure(oop); |
| |
| // In the absence of promotion failure, we wouldn't look at "from-space" |
| // objects after a young-gen collection. When promotion fails, however, |
| // the subsequent full collection will look at from-space objects: |
| // therefore we must remove their forwarding pointers. |
| void remove_forwarding_pointers(); |
| |
| // Preserve the mark of "obj", if necessary, in preparation for its mark |
| // word being overwritten with a self-forwarding-pointer. |
| void preserve_mark_if_necessary(oop obj, markOop m); |
| void preserve_mark(oop obj, markOop m); // work routine used by the above |
| |
| // Together, these keep <object with a preserved mark, mark value> pairs. |
| // They should always contain the same number of elements. |
| Stack<oop, mtGC> _objs_with_preserved_marks; |
| Stack<markOop, mtGC> _preserved_marks_of_objs; |
| |
| // Promotion failure handling |
| ExtendedOopClosure *_promo_failure_scan_stack_closure; |
| void set_promo_failure_scan_stack_closure(ExtendedOopClosure *scan_stack_closure) { |
| _promo_failure_scan_stack_closure = scan_stack_closure; |
| } |
| |
| Stack<oop, mtGC> _promo_failure_scan_stack; |
| void drain_promo_failure_scan_stack(void); |
| bool _promo_failure_drain_in_progress; |
| |
| // Performance Counters |
| GenerationCounters* _gen_counters; |
| CSpaceCounters* _eden_counters; |
| CSpaceCounters* _from_counters; |
| CSpaceCounters* _to_counters; |
| |
| // sizing information |
| size_t _max_eden_size; |
| size_t _max_survivor_size; |
| |
| // Allocation support |
| bool _should_allocate_from_space; |
| bool should_allocate_from_space() const { |
| return _should_allocate_from_space; |
| } |
| void clear_should_allocate_from_space() { |
| _should_allocate_from_space = false; |
| } |
| void set_should_allocate_from_space() { |
| _should_allocate_from_space = true; |
| } |
| |
| // Tenuring |
| void adjust_desired_tenuring_threshold(); |
| |
| // Spaces |
| EdenSpace* _eden_space; |
| ContiguousSpace* _from_space; |
| ContiguousSpace* _to_space; |
| |
| STWGCTimer* _gc_timer; |
| |
| enum SomeProtectedConstants { |
| // Generations are GenGrain-aligned and have size that are multiples of |
| // GenGrain. |
| MinFreeScratchWords = 100 |
| }; |
| |
| // Return the size of a survivor space if this generation were of size |
| // gen_size. |
| size_t compute_survivor_size(size_t gen_size, size_t alignment) const { |
| size_t n = gen_size / (SurvivorRatio + 2); |
| return n > alignment ? align_size_down(n, alignment) : alignment; |
| } |
| |
| public: // was "protected" but caused compile error on win32 |
| class IsAliveClosure: public BoolObjectClosure { |
| Generation* _g; |
| public: |
| IsAliveClosure(Generation* g); |
| bool do_object_b(oop p); |
| }; |
| |
| class KeepAliveClosure: public OopClosure { |
| protected: |
| ScanWeakRefClosure* _cl; |
| CardTableRS* _rs; |
| template <class T> void do_oop_work(T* p); |
| public: |
| KeepAliveClosure(ScanWeakRefClosure* cl); |
| virtual void do_oop(oop* p); |
| virtual void do_oop(narrowOop* p); |
| }; |
| |
| class FastKeepAliveClosure: public KeepAliveClosure { |
| protected: |
| HeapWord* _boundary; |
| template <class T> void do_oop_work(T* p); |
| public: |
| FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl); |
| virtual void do_oop(oop* p); |
| virtual void do_oop(narrowOop* p); |
| }; |
| |
| class EvacuateFollowersClosure: public VoidClosure { |
| GenCollectedHeap* _gch; |
| int _level; |
| ScanClosure* _scan_cur_or_nonheap; |
| ScanClosure* _scan_older; |
| public: |
| EvacuateFollowersClosure(GenCollectedHeap* gch, int level, |
| ScanClosure* cur, ScanClosure* older); |
| void do_void(); |
| }; |
| |
| class FastEvacuateFollowersClosure: public VoidClosure { |
| GenCollectedHeap* _gch; |
| int _level; |
| DefNewGeneration* _gen; |
| FastScanClosure* _scan_cur_or_nonheap; |
| FastScanClosure* _scan_older; |
| public: |
| FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level, |
| DefNewGeneration* gen, |
| FastScanClosure* cur, |
| FastScanClosure* older); |
| void do_void(); |
| }; |
| |
| public: |
| DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level, |
| const char* policy="Copy"); |
| |
| virtual void ref_processor_init(); |
| |
| virtual Generation::Name kind() { return Generation::DefNew; } |
| |
| // Accessing spaces |
| EdenSpace* eden() const { return _eden_space; } |
| ContiguousSpace* from() const { return _from_space; } |
| ContiguousSpace* to() const { return _to_space; } |
| |
| virtual CompactibleSpace* first_compaction_space() const; |
| |
| // Space enquiries |
| size_t capacity() const; |
| size_t used() const; |
| size_t free() const; |
| size_t max_capacity() const; |
| size_t capacity_before_gc() const; |
| size_t unsafe_max_alloc_nogc() const; |
| size_t contiguous_available() const; |
| |
| size_t max_eden_size() const { return _max_eden_size; } |
| size_t max_survivor_size() const { return _max_survivor_size; } |
| |
| bool supports_inline_contig_alloc() const { return true; } |
| HeapWord** top_addr() const; |
| HeapWord** end_addr() const; |
| |
| // Thread-local allocation buffers |
| bool supports_tlab_allocation() const { return true; } |
| size_t tlab_capacity() const; |
| size_t unsafe_max_tlab_alloc() const; |
| |
| // Grow the generation by the specified number of bytes. |
| // The size of bytes is assumed to be properly aligned. |
| // Return true if the expansion was successful. |
| bool expand(size_t bytes); |
| |
| // DefNewGeneration cannot currently expand except at |
| // a GC. |
| virtual bool is_maximal_no_gc() const { return true; } |
| |
| // Iteration |
| void object_iterate(ObjectClosure* blk); |
| void object_iterate_since_last_GC(ObjectClosure* cl); |
| |
| void younger_refs_iterate(OopsInGenClosure* cl); |
| |
| void space_iterate(SpaceClosure* blk, bool usedOnly = false); |
| |
| // Allocation support |
| virtual bool should_allocate(size_t word_size, bool is_tlab) { |
| assert(UseTLAB || !is_tlab, "Should not allocate tlab"); |
| |
| size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize); |
| |
| const bool non_zero = word_size > 0; |
| const bool overflows = word_size >= overflow_limit; |
| const bool check_too_big = _pretenure_size_threshold_words > 0; |
| const bool not_too_big = word_size < _pretenure_size_threshold_words; |
| const bool size_ok = is_tlab || !check_too_big || not_too_big; |
| |
| bool result = !overflows && |
| non_zero && |
| size_ok; |
| |
| return result; |
| } |
| |
| HeapWord* allocate(size_t word_size, bool is_tlab); |
| HeapWord* allocate_from_space(size_t word_size); |
| |
| HeapWord* par_allocate(size_t word_size, bool is_tlab); |
| |
| // Prologue & Epilogue |
| virtual void gc_prologue(bool full); |
| virtual void gc_epilogue(bool full); |
| |
| // Save the tops for eden, from, and to |
| virtual void record_spaces_top(); |
| |
| // Doesn't require additional work during GC prologue and epilogue |
| virtual bool performs_in_place_marking() const { return false; } |
| |
| // Accessing marks |
| void save_marks(); |
| void reset_saved_marks(); |
| bool no_allocs_since_save_marks(); |
| |
| // Need to declare the full complement of closures, whether we'll |
| // override them or not, or get message from the compiler: |
| // oop_since_save_marks_iterate_nv hides virtual function... |
| #define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ |
| void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); |
| |
| ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL) |
| |
| #undef DefNew_SINCE_SAVE_MARKS_DECL |
| |
| // For non-youngest collection, the DefNewGeneration can contribute |
| // "to-space". |
| virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor, |
| size_t max_alloc_words); |
| |
| // Reset for contribution of "to-space". |
| virtual void reset_scratch(); |
| |
| // GC support |
| virtual void compute_new_size(); |
| |
| // Returns true if the collection is likely to be safely |
| // completed. Even if this method returns true, a collection |
| // may not be guaranteed to succeed, and the system should be |
| // able to safely unwind and recover from that failure, albeit |
| // at some additional cost. Override superclass's implementation. |
| virtual bool collection_attempt_is_safe(); |
| |
| virtual void collect(bool full, |
| bool clear_all_soft_refs, |
| size_t size, |
| bool is_tlab); |
| HeapWord* expand_and_allocate(size_t size, |
| bool is_tlab, |
| bool parallel = false); |
| |
| oop copy_to_survivor_space(oop old); |
| uint tenuring_threshold() { return _tenuring_threshold; } |
| |
| // Performance Counter support |
| void update_counters(); |
| |
| // Printing |
| virtual const char* name() const; |
| virtual const char* short_name() const { return "DefNew"; } |
| |
| bool must_be_youngest() const { return true; } |
| bool must_be_oldest() const { return false; } |
| |
| // PrintHeapAtGC support. |
| void print_on(outputStream* st) const; |
| |
| void verify(); |
| |
| bool promo_failure_scan_is_complete() const { |
| return _promo_failure_scan_stack.is_empty(); |
| } |
| |
| protected: |
| // If clear_space is true, clear the survivor spaces. Eden is |
| // cleared if the minimum size of eden is 0. If mangle_space |
| // is true, also mangle the space in debug mode. |
| void compute_space_boundaries(uintx minimum_eden_size, |
| bool clear_space, |
| bool mangle_space); |
| // Scavenge support |
| void swap_spaces(); |
| }; |
| |
| #endif // SHARE_VM_MEMORY_DEFNEWGENERATION_HPP |